ALERT For Strong Winds Developing Friday Night Into Saturday Morning At Mid-Upper Elevations Along The Cumberland Mountains
An increasing pressure gradient in advance of a strong cold front and the coldest air mass of this season will cause the development of strong winds at higher elevations in the Cumberland Mountains during Friday Night into Saturday. Caution is advised.
Potential For Accumulating Snow Increasing
A strong cold front and upper air trough is expected to transport unseasonably cold air southward into the mountains this weekend into the beginning of next week as bombogenesis occurs over the New England states. NW-N upslope flow will bring sticking snow into the eastern highlands of West Virginia, with the potential now increasing for accumulating snow farther south along the mountains to the High Knob Massif, Mount Rogers, Roan-Hump Mountain, into the top of the Great Smokies.
Overnight Into Friday Morning
Mostly clear ( a few high clouds ). SSW-SW winds 5-15 mph, with higher gusts, on mountain ridges & exposed plateaus below 2700 feet. SSW-SW winds 10-20 mph, with higher gusts, on upper elevation mountain ridges. Temps varying from upper 20s to mid 30s in valleys to 40s along exposed ridges & plateaus. Wind chills in the low-mid 30s along higher mountain ridges.
Friday Afternoon
Mostly sunny. Blue skies. Gusty winds. SSE-SSW winds at 5 to 15 mph, with higher gusts on mountain ridges. Temps varying from 50s at upper elevations to the mid-upper 60s.
Friday Night Into Saturday Morning
Increasing clouds with rain developing by morning. Windy. SSE-SSW winds increasing to 10-20 mph, with higher gusts, at elevations below 2700 feet. SSE to SW winds 20-30 mph, with higher gusts, along mid-upper elevation mountain ridges. Temperatures falling into the 40s to lower 50s by morning. Wind chill factors in the 30s to lower 40s at upper elevations.
Saturday Morning Through The Afternoon
Rain. Local downpours. Turning colder. Winds shifting NW at 5 to 15 mph, with higher gusts, by mid to late afternoon. Temperatures dropping into the 30s to middle 40s ( coldest at higher elevations ). Low cloud bases with widespread dense fog across upper elevations. Nasty!
*The potential of the first accumulating snow is increasing for middle-upper elevations ( above 2000-3000+ feet ).
Saturday Night Into Sunday Morning
Cold & blustery with rain showers changing to snow showers and flurries. NW-NNW winds 5-15 mph, with higher gusts, along mid-upper elevation mountain ridges and plateaus. Temperatures varying from the lower 20s to lower 30s ( coldest at highest elevations ). Milder south into river valleys of the Clinch, Powell, Holston drainages. Wind chills in the 10s & 20s, except dropping to around 10 degrees or lower on peaks above 3600 feet. Rime formation in the upper elevations above 3300 feet.
NOTE – A widespread freeze occurred into Thursday morning so I will no longer be highlighting any alerts related to frost-freezing conditions.
Weather Discussion ( Wintry Blast )
A drastic change in the weather is expected between a very nice TGIF ( outside of high country wind chills ) and a nasty Saturday into Sunday period.
Black Mountain Mesonet – 1 Hour Observations Ending At 12:20 AM Friday ( Oct 27 )
Changes related to this big weather shift are already being felt in upper elevations tonight, via gusty winds, with an initial sharp temperature drop in high valleys now being replaced by temp rises with recoupling of all but the most sheltered valley boundary layers.
European Model 850 MB-Surface Analysis At 8 AM Thursday – October 26, 2017
The first snowflakes of the season fell in the high country of the High Knob Massif during October 25 as the first of two cold pushes crossed the mountains ( the next one just emerging upstream near the Canadian border, above, will certainly be the most vigorous ).
Clearing skies into Thursday Morning ( October 26 ) allowed temps to drop into the 20s in many mountain valleys, with a hard freeze being observed in Clintwood, Norton, Tacoma-Coeburn and many other places ( coldest temps were recorded in high valleys above 3000 feet in the high country of the High Knob Massif ).
European 51-Member Ensemble Mean 500 MB Height Anomalies – 8 AM Oct 29
Details of the upcoming pattern are still being worked out by the models, but it is clear that a deep upper trough and disturbance will dig into the eastern USA into Sunday.
The first snow accumulations of the season look nearly certain now for higher elevations in the eastern highlands of central & northern West Virginia, with the only question being how far south along the Appalachians will this extend into Sunday.
Regardless of the snow potential, conditions will become increasingly NASTY as Saturday passes into Saturday Night and Sunday Morning with true winter temperatures and wind chills to impact the mountain region. Get Ready!
